Art of cracking hydrocarbons



. Nov. 8; 1932. E. c. HERTHEL ET AL 3 3 v ART OF CRACKING HYDRQCARBONS File d Sept. 14, 1928 2 Sheets-Sheet 1 .INVENTO \GAMA ATTORNEYS Nov. 8, 1932. E. c. HERTHEL ET AL ART OF CRACKING HYDROCARBONS Filed Sept. 14. 1928 2 Sheets-Sheet 2 Patented Nov. 8,1932

UNITED STATES PATENT OFFICE EUGENE c. HEBTHEL, or cnIoAGo, ILLINOIS, AND HARRYL. rELzEn, or meHLA'Nn, INDIANA, AssIGNoRs, BY MESNE ASSIGNMENTS, 'ro THE GRAY rnocnssns conro RATION, or Nnwanx, NEW JERSEY, A conromrroN or DELAWARE ART OF CR ACKING HYDROCABBONS Application filed September 14, 1928. Serial No. 305,902.

This invention relates .to improvements in the manufacture of gasoline; more particularly the invention relates to improvements in the combined cracking of oil in vapor phase under severe cracking conditions to produce motor fuel gasoline and refining of the thus produced gasoline by passage through'an adsorptive catalyst in vapor phase.

When raw cracked gasoline or a fraction containing raw cracked gasoline, particularly gasoline produced by severe vapor phase cracking, is passed in vapor phase through an adsorptive catalyst such as fullers earth, certain unsaturated constituents such as the di-olefines, to the extent that they are present,

I are polymerized to form higher boiling polymers. This reaction affords a means of separating such constituents without involving loss of other unsaturated.constituents of special value as components of motor fuel gasoline. The separation of the polymers pro duced by the vapor-catalyst contact is usual- 1y accomplished by fractional condensat1on or liquefaction, either in the refining operation proper or in some subsequent fractionating operation. 7

This invention provides an improved method of carrying out this general refining method in combination with vapor phase cracking operations. The invention has several advantages; it simplifies the apparatus required and improves operating economy and operating efliciency.

- According to the present invention, where.

a number of vapor phase cracking systems are operated concurrently, instead of subjecting the raw gasoline or raw gasoline-containing fractions from each of the several vapor phase cracking systems to the refining operation before condensation, the raw gasoline or raw gasoline-containing fraction from but one of the vapor phase cracking systems of the group is so subjected directly to the refining opera tion before condensation and the raw gasoline or raw gasoline-containing fraction from the other vapor phase cracking systems of the group is condensed and the condensate appropriately introduced. into the first mentioned vapor phase cracking system, revaporized therein and subjected to the refining operation in admixture with the va ors therefrom. A number of advantages, incFuding particularly those previously mentioned, are thus secured by the invention. In one aspect, the invention provides a particularly advantageous method of refining as a composite the raw products from a plurality of concurrently operated but otherwise independent vapor phase cracking systems.

The invention will be described in connection with the accompanying drawings which illustrate, diagrammatically and conventionally, one form of apparatus adapted for carrying out the process of the invention. It will be understood that the process of the invention canbe carried out imother and different apparatus and that this particular apparatus, although particularly useful in carrying out the invention, is intended but to illustrate the invention.

Fig. 1 of the drawings illustrates vapor phase cracking and refining apparatus adapted to be operated in accordance with the process of the invention when a raw unrefined gasoline-containing condensate from another vapor phase cracking-apparatus is supplied to the pump 44.

Fig. 2 illustrates a vapor phase cracking apparatus similar to that illustrated in Fig. 1, but not provided with vapor phase refining apparatus. The apparatus illustrated in Fig. 2 is adapted to produce a raw unrefined gasoline-containing condensate and to be operated in conjunction with the apparatus ilwhich the vap'o r'phase cracking operation proper is carried out, a scrubbing tower 3 for the separation of tar and tarry matter, a. reflux tower or fractionating tower 4, a re- I struction,

fining tower 5, a fractionating tower 6, a condenser 7 and a receiver 8.

The heating furnace 2 comprises a firebox 9 communicating with the upper end of the heating flue inv which the heating conduit 1 is arranged and a fan 10 for withdrawing heating gases from the lower end of this heating flue and for recirculating'part of the heating gases therethrough by means of the several branch connections shown and for discharging the balance through the stack 12. Fan 11 is provided forsupplying the air required for combustion through a preheating heat exchanger in the stack 12. Other types of vapor phase cracking apparatus may be usedin carrying out the invention; for example a combined heating conduit and connected series of digesting drums as described,

in an application filed June 13, 1927, by Harry L. vPelzer, Serial No. 198,621, may be used in carrying out the invention.

v The tower 3 may be'of open ba-flle construct f the so-called bubble plate construction, for example. The towers 4 and '6' are with advantage of bubble plate conor other construction adapted to secure close fractionation. The tower 5 is adapted to receive and support a charge of adsorptive catalyst, 40450 or 608O mesh fullers earth for example, upon a foraminous partition 15. A plurality of towers; similar to tower 5 with suitable manifolds may be provided to permit maintained continuity of operation while cleaning or while replacing spentcatalyst. The towers 3 and 4 are shown surmounted by dephlegmators 13 and 14 providedwith cooling coils. These dephlegmators may be made a unitary part of the tower structure proper or they may bedispensed with and refluxing provided by the direct introduction of a refluxing agent, for example. The dephlegmators however are advantageous particularly in aifording close control of the operation. The several towers 3, 4, 5 and 6 and'thedephlegmators 13 and 14 as well as the hot connections between them are with advantage lagged or thermally insulated to minimize heat loss and to assist in maintainmg close control of the operation. The condenser 7 and receiver 8 should be of types adapted to handle the amount of very low boihng vapors and gases produced in the particul ancracking operation.

Oll 1s supplied to the heating conduit 1 through connection 16 and the hot oil products are discharged therefrom into the lower end of tower 3 through connecton 17. Vapors pass from the upper end of tower 3 to the lower end of tower 4 through connection 18, from the upper end of tower 4 to the upper end of tower 5 through connection 19,from the lower end of tower 5 to the lower end of tower 6 through connection 20 and from the upper end of tower 6 to the condenser 7 through connection 21. The condenser 7 disreceiver through apparatus,

regulated circulation of one or charges into receiver 8 through connection 22. The condensate is discharged. from thls densed vapors and gases through connection 24:.

In the particular cracking apparatus illustrated, the oil may be supplied to the heating conduit under a pressure just suflicient to force. the oil and the oil products through the heating conduit and through the rest of the 60-80 pounds per square inch, example. The oil products may be discharged from the heating conduit at a temperature approximating 10001100 F.

In carrying out the invention in the appa 'ratus illustratedyraw oil is supplied through connection 25 and, by means of pump 26,

connection 23 and moon-- for I forced through the heating conduit 1 together with any refluxed "fractions supplied through connections 27 and 28. The hot oil products are discharged from the heating conduit into the lower end of tower 3 through a liquid pool of tar maintained therein. Tar and tarry matter are separated in the tower 3 and discharged through connection 29. The opera tion of this tower may be controlled by the regulated introduction of a refluxing agent or agents through connection 30 or by the more cooling media through the cooling coils 31 and 32 or by any combination of these means. Condensate produced in the dephlegmator 13 is returned to the upper end of tower 3 through connection 33. The remaining vapors eed from .tar or tarry matter escape from' the upper end of tower 3 to the lower end of tower 4 in which heavier oil components are condensed. This condensate is discharged through connection 34:; it may be reintroduced or in part reintroduced into the upper end of tower 3 through connections 35. 36 and 30 by means of pump 37, or supplied or in part supplied to the heating conduit 1 together with raw oil through connections and 28 by means of pump 37, or discharged or in part discharged through connection 38. The operation of this tower may be controlled by regulated introduction ofa refluxing agent or agents through connection 39 or by circulation of one or more cooling media through'the cooling coils 40 or 41 or by any combination of these means. The temperature of'the vapors escapingthrough connection 18 may be maintained in the neighborhood of 500550 F., for example,

and the temperature of the vapors escaping through loo ucts from one, two or more other vapor phase cracking systems operating concurrently with that illustrated and producing a similar raw product are introduced into the upper end of tower 4 through connection 42 or 43 or both of them by means of pump 44. This unre fined product may be introduced directly into the upper end of tower 4 through connection 43 or it may first be circulated, in whole or in part, through the cooling coils 31 and 40, or either of them, in the dephlegmaors 13 and 14 and then introduced into the upper end of tower 4 through connection 42. For example, this unrefined productor part of it may be circulated through either of the cooling coils -31 and 40 or' through both of them in parallel or first through cooling coil 40 and then through cooling coil 31 before introduction into the upper end of tower 4 through connection 42, by means of the connections and valves illustrated including connections 45, 46 and 47.

Another cooling medium may similarly be circulated through either of the cooling coils 32 and 41 or through both of them in parallel or first through the cooling coil 41 and then through the cooling coil 42 in series, by means of the connections and "alves illustrated. An extraneous cooling medium, water for example, may be supplied to these cooling coils by means of pump 48 and discharged through connection 49. or apart of the raw oil to be supplied to the heating conduit 1 may be supplied to these cooling coils by means of pump48 and discharged into the oil enteri5l(l)g the heating conduit 1 through connection The condensate mator 14 may be of tower 4 through produced in the dephlegreturned to the upper end connection 51 or, by means of connections 52 and 53. this condensate or part of it may with advantage be passed through the charge of adsorptive catalyst in the tower 5 asa washing agent to assist in maintaining the activity of the catal st. If necessaryor desirable, an extraneouswashing agent can be supplied to the tower 5 through connections 54 and 53 by means of pump 55.

In the refining tower 5, the vapors from the upper end of tower 4 including the vapors of the oil introduced through connections 42 and 43, are passed in contact with the charge of adsorptive catalyst therein thus subjecting the undesirable"constituents of these vapors to polymerization forming of them higher boiling polymers. This high boiling material may be separated in the tower 5 and discharged through connection 56 or the resulting oil products including this high boiling material may be discharged as a composite into the lower end of tower-6 through connection 20. Where-the high boiling material is separated in tower 5, the remaining vapors are discharged into the lower end of tower 6 through connection 20. V

In tower 20, the vapor mixture supplied thereto is subjected to a fractionating operation for the production of a product, collected in receiver8, of the desired boiling range.

lected in receiver 8, for example, may be so supplied to the upper end of tower 6 as a. refluxing agent through connections 23, 58 and 57 by means of pump 59 or some extraneous refluxing agent, a refined gasoline of corre-- 1 spondnig boiling range from some other operation, for example, may be so supplied as a refluxing agent through connections 60 and 57 by means of pump 59. The condensate collecting in the lower end of tower 6 is discharged through connection 61.

Where the high boiling material produced by the vapor catalyst contact in tower 5 is separated in tower 5 and dischar ed through connection 56,this material is wit advantage introduced into the upper end of tower 3 through connections 62, 63 and 30 by means of pump 64 in whole or in part, or it may be discharged through connection 65.- Where the condensate discharged from tower 6 through connection 61 includes a substantial portion of high boiling polymers produced by the vapor catalyst contact in tower 5, it is with advantage introduced into the upper end of tower 3 through connections 66, 67, 63 and 30 by meansof pump 68, in whole or in part, or it may be discharged through connection 69. Where it isrelatively free from such high boiling polymers, it may similarly be introduced into the upper end of tower 3 through these connections, in whole or in part, or it may be supplied, in whole or in part, to the heating conduit 1 through connections 66 and 27.

tions are condensed, and these raw condensates are introduced lnto'this fractionating operation in direct contact with the vapors therein, these condensates being revaporized in the fractionating operation and subjected to the refining operation in admixture with the vapors therefrom; in the apparatus illustrated for example, the raw condensates from other vapor phase cracking operations are introduced into the tower 4 through which vapors including the vapors of the desired product from the heating conduit 1 pass being vaporized therein and passed through the refining tower 5 in admixture with vapors from the heating conduit 1. The raw con- The other vapor phase cracking operations of the group may be carried out, for example, 7

in apparatus similar to that illustrated and similarlyoperated but in which the tower 5 and the tower 6 are omitted and in which the vapors escaping from a tower corresponding to tower i pass directly to a condenser corresponding to condenser 7. In such other vapor phase cracking operations the towers corresponding to towers 3 and 4. may, for example, be controlled the same as towers 3 and i; other or additional refluxing means of course being used in the towers corresponding to tower 4. It is an advantage of the invention that independent control of the several vapor phase cracking operations proper is afforded although the refining operations are combined and carried out as a .single operation. apparatus adapted to carry out one such other vapor phase cracking operation is illustrated in Fig. 2 which shows a Vapor phase cracking apparatus similar to that illustrated in Fig. 1 and in are designated by the same reference numerals with the letter a appended thereto. In the operation of such other vapor phase cracking apparatus control of the tower 4a may be assisted by introducing a part of the rawunrefined gasoline-containing distillate to the' tower from receiver The raw condensates from the other vapor phase cracking operations of the group are with advantage passed in indirect heat exchange With the vapors from the vapor phase cracking operation directly connected with the refining operation before introduction into the fractionating operation of that sys- .8a through connection tem. The raw condensates, for example,

may be passed in indirect heat exchange with the vapors in the fractionating operation before introduction into the fractionating operation. The raw condensates are, with particular advantage, passed in indirect heat exchange with the vapors from this vapor phase cracking operation, for example in a tar separating operation, before these vapors are subjected to the fractionating operation. The raw condensates may be introduced into the fractionat-ingoperation, for example,-after passlng in indirect heat'exchange with the vapors escaping from the fractionating operation, or after passing in indirect heat exchange with thevapors escaping from a preceding tar separating operation and entering the fractionating operation, or after passing in indirect heat exchange with the vapors escaping from the 'fractionating operation and from a preceding tar separating opera tion, or after passing first in indirect heat exchange with the vapors escaping from the which corresponding parts I fractionating operation and then in indirect heat exchange with the'vapors escaping from a preceding tar separating operation; in the apparatus illustrated for example, the raw condensates may be introduced into tower 4 after passing through cooling coil 40 or after passing through cooling coil 31 or after passing through cooling coils 40 and 31 in parallel or after passing first through cooling coil 40 and then through cooling coil 31.

The invention also makes possible of practical achievement an important improvement with respect to uniformity of the product. In the combined operation of the invention the refining operation is simplified in several respects; a single refining operation is made to do the work of a plurality of separate refining operations and the increased throughput of the refining operation not only makes easier the maintenance of uniform operating conditions in the refining operation but also makes less important with respect to the character of the refined product produced variations in the character of the raw product produced by any one of the vapor phase cracking operations of the group. Inthis respect, also, the final fractionationpf the refined composite produced by the group of vapor phase cracking operations in a single finishing fractionating operation, carried out in tower 6 in the apparatus illustrated, further assists in maintaining uniform the refined product.

We claim: -1. In the combin d vapor phase cracking of oil to produce gasoline and refining of the thus produced gasoline by passage through an adsorptive catalyst in vapor phase, the improvement which comprises concurrently conducting'a plurality of vapor phase cracking operations, subjecting the raw gasolinecontaining vapors from one pf these vapor phase cracking operations successively to a scrubbing operation for separation of tar, to a fractionating operation for condensation of constituents higher boiling than gasoline and then to a refining operation in which the vapors are passed through the adsorptive catalyst and condensing refined gasoline from the refined vapors escaping from the refining operation, condensing the raw gasoline-containing vapors from another of these vapor phase cracking operations to form a raw gasoline-containing condensate, passing this raw gasoline-containing condensate in indirect heat exchange with the vapors escaping from the said scrubbing operation and introducing the thus preheated raw gasoline-containing condensateinto direct contact with the vapors in the said fractionating operation, whereby this raw gasoline-containing condensate is revaporized in the said fractionating operation and the resulting vapors are passed are condensed with the gasoline-containing vapors from the first separately mentioned vapor phase cracking operation.

2. In the combined vapor phase cracking of oil to produce gasoline and refining of the thus produced gasolineby passage through an adsorptive catalyst in vapor phase, the improvement which com rises concurrently conducting a plurality'of vapor phase cracking operations, subjecting the raw gasolinecontaining vapors from one of these vapor phase cracking operations successively to a scrubbing operation for separation of tar, to a fractionating operation for condensation of constituents higher boiling than gasoline and then to a refining operation in which the vapors are passed through the adsorptive catalyst and condensing refined gasoline from the refined vapors escaping from the refining operation, condensing the raw gasoline-containing vapors from another of these vapor phase cracking operations to form a raw gasolinecontaining condensate, passing this raw gasoline-containing condensate in indirect heat exchange first with the vapors escaping from the said fractionating operation and then with the vapors escaping from the said scrubbing operation and introducing the thus preheated raw gasoline-containing condensate into direct contact with the vapors in the said fractionating operation, whereby this raw gasoline-containing condensate is revaporized in the said fractionating operation and the resulting vapors are passed through the adsorptive catalyst in the said refining operation and these refined vapors are condensed with thegasoline-containing vapors from the first separately mentione vapor phase cracking operation.

3. In the combined vapor phase cracking of oil to produce gasoline and refinin of the thus produced gasoline by passage t rou h an adsorptive catalyst in vapor phase, t e improvement which comprises concurrently conducting a plurality of vapor phase cracking operations, subjecting the raw gasolinecontaining vapors from one of these vapor phase cracking operations successively to a scrubbing operation for se aration of tar,

' to a fractionating o eration or condensation of constituents hi er boiling than asoline and then to a refimng operation in w ich the vapors are passed through the adsorptive catalyst and condensing refined gasoline from the refinedvapors escaping from the refining operation, condensing the raw. asoline-containing va ors from another 0 these vapor phase crac ing operations to form a 'raw gasoline-'containmg condensate, passing this raw gasoline-containing condensate in indirect heat exchange with the vapors escapin from the said fractionating operation an the said scrubbing operation and introducing the thus preheated raw gasoline-containing condensate into direct contact with the vaporsin the said fractionating operation, whereby this raw gasoline-containing condensate is revaporized in the said fraction ating operation and the resulting vapors are passed through the adsorptive catalyst in the said refining operation and these refined vapors are condensed with the gasoline-containing vapors from the first separately mentioned vapor phase cracking operation.

4. In the combined vapor phase cracking of oil to produce gasoline and refining of the thus produced gasoline by passage throu h an adsorptive catalyst in vapor phase, t e improvement which comprises concurrently 8o conducting a plurality of vapor phase crack- 1ng operations, subjecting the raw gasolinecontaining vapors from one of these vapor phase cracking operations successively to a fractionating operation for condensation of constituents higher boiling than gasoline and then to a refining operation in which the vapors are passed'through the adsorptive catalyst and condensing refined gasoline from the refined vapors escaping from the refining co operation, condensing the raw gasoline-containing vapors from another of these vapor phase cracking operations to form a raw gasoline-containing condensate, passing this raw gasoline-containing condensate in indirect heat exchange with the vapors escapin from the said fractionating operation an introducing the thus preheated raw gasolinecontaining condensate into direct contact with the vapors in the said fractionating operation, whereby this raw gasoline-containing condensate is revaporized in the said fractionatingoperation and the resulting vapors are passed through the adsorptive catalyst in the said refining operation and these 5 refined vapors are condensed with the gasoline-containing vapors from the first separately mentioned vapor phase cracking operation, and passing condensate produced by the said heat exchange through the adsorptive catalyst during the refinin operation.

In testimony whereof we a our signatures. I

EUGENE C. HERTHEL. HARRY L. PELZER. 

